2023 年 3 巻 1 号 p. 35-42
Purpose: Minimally invasive endodontics (MI Endo) has been advocated on the basis that minimal cutting of tooth substance prevents root fracture after endodontic therapy. The purpose of this study was to analyze the shaping ability of thermo-mechanically treated controlled memory (CM) wire nickel-titanium (NiTi) files using MI Endo.
Methods: Using a J-shaped root canal model, ProTaper Gold (PTG) and ProTaper Ultimate (PTU) files made of CM wire were used in the experimental group, and ProTaper Universal (PT) files made of conventional NiTi wire were used in the control group, and their cutting properties were compared. The PTU, PTG, and PT groups were further classified into two subgroups (with and without straight line (SL) access), and the root canal width displacement and median displacement were compared between the six groups in total.
Results: For the PTU and PTG groups, the root canal width displacement on the lateral side slightly increased at the 1 mm apical measurement, and there was a significant difference between the displacement on the inner and outer sides at 3-8 mm. However, in the PT control group, the displacement on the inner side increased at 3-5 mm, and the displacement on the outer side increased at 1 and 8 mm. We compared the root canal width displacement in the PTU, PTG, and PT groups between those with and without SL access, but no significant differences were observed. Comparison between the SL and no-SL PTU, PTG, and PT groups revealed no significant differences in root canal width displacement or median displacement at any of the measurement sites.
Conclusions: PTU and PTG made with CM wire resulted in accurate root canal formation with no-SL access.
